Lithostratigraphy of the Great Estuarine Group (Middle Jurassic), Inner Hebrides

Abstract

Synopsis Revised lithostratigraphical terminology for the Great Estuarine Group in Skye, Raasay, Eigg and Muck is proposed. The group comprises the Cullaidh Shale Formation, Elgol Sandstone Formation with Kildonnan Member and Lonfearn Member, Valtos Sandstone Formation, Duntulm Formation, Kilmaluag Formation and Skudiburgh Formation. The type sections of these formations are defined, new measured sections of 5 of them are illustrated and their lateral variations described. The Group is predominantly Bathonian in age, having its base in the Garantiana Zone (Upper Bajocian) and its top in the Macrocephalus Zone (Lower Callovian). The mainly argillaceous formations show wide lateral continuity indicating that a single depositional basin must have occupied the Inner Hebrides—Minch area during the Bathonian.

Dinosaur Tracks from the Kilmaluag Formation (Bathonian, Middle Jurassic) of Score Bay, Isle of Skye, Scotland, UK

“…2. Diagramatic representation of the Middle Jurassic stratigraphy of the north of the Isle of Skye, with approximate thicknesses, showing levels from which dinosaur bones and footprints have been found (based on Harris and Hudson, 1980;Andrews and Walton, 1990;and Cox, 2002). Vertical scale in 25 m sections.…”

“…Stratigraphic correlation within the Kilmaluag Formation in Trotternish is problematic due to the discontinuous nature of the sedimentary succession (Anderson and Dunham, 1966;Harris and Hudson, 1980). Although the type section in the Kilmartin River (Anderson, 1963;Anderson and Dunham, 1966) exhibits about 26m of succession, the strata are disturbed and broken by offshoots from a sill that underlies the Kilmaluag Formation in that area.…”

“…Although the type section in the Kilmartin River (Anderson, 1963;Anderson and Dunham, 1966) exhibits about 26m of succession, the strata are disturbed and broken by offshoots from a sill that underlies the Kilmaluag Formation in that area. The best and most easily accessible exposures of this formation are those in Kilmaluag Bay (Harris and Hudson, 1980;Morton and Hudson, 1995), although exposure is tidal and can vary depending on beach sediment cover. The section at Lub Score cannot be confidently correlated with any particular beds from these localities.…”

The anatomy of the basal turtle Eileanchelys waldmani from the Middle Jurassic of the Isle of Skye, Scotland

“…This formation is part of the Great Estuarine Group (GEG), which consists of a sequence of Middle Jurassic paralic deposits on the islands of the Inner Hebrides, NW Scotland. The GEG crops out in the isles of Skye, Raasay, Eigg and Muck and is intercalated conformably within the marine Jurassic section of the Minch Basin (Harris & Hudson 1980;Hudson 1983). The GEG is remarkable as it yields no m a r ine fa una but bra c kis h a nd/ o r fre s hwa te r assemblages; it is the only part of the Jurassic section of the Minch Basin that is not fully marine (Harris & Hudson 1980).…”

“…1). Cladach a'Ghlinne represents the best exposure of the Kilmaluag Formation, which is of late Bathonian age (Harris & Hudson 1980;Andrews 1985).…”